This invention relates to the application of protective coatings to vehicles, and, more particularly, to a method and apparatus for applying wax or similar protective coatings to the inner cavities of rear deck lids and other body components of vehicles.
It is common practice among vehicle manufacturers to apply wax or other protective coatings to the inner cavities of vehicle body components such as doors, rear deck and hatchback lids, hoods, fender panels and underbodies. The goal is to provide a uniform, uninterrupted coating along the hem flange areas of such components and other areas where water and corrosive materials are most likely to collect.
In most vehicle assembly lines, protective coatings are currently applied to body components manually by an operator using a hand held spray gun. The major problem with this practice is that the coating material is often applied unevenly, and, in some instances, voids are created where no coating is applied to the body component. This is particularly true in coating doors or other body components of irregular shape which include a number of crevices along their inner cavities.
One solution to the problems associated with manual coating operations has been proposed, for example, in German Patent No. 2,827,770. In the German patent, an automatic coating system is proposed in which the position and movement of at least one spray gun is mechanically controlled, and the volume of protective coating supplied to the spray guns for discharge onto the body component is variable depending on the configuration of the body component to be coated.
Mechanical spray coating systems of the general type described above reduce the problem of uneven or interrupted coating of vehicle components associated with current manual coating techniques. However, no provision is made in the German patent, or other systems known to applicant, to assure proper positioning of the spray guns relative to the body component to be coated, or proper spray patterns where multiple spray guns are employed. Specifically, such systems do not provide for an indication of the proper positioning of the apparatus and/or the spray guns prior to the initiation of a coating operation. Unless the spray guns are properly oriented with respect to the vehicle body component to be coated, the protective coating may not be applied at the desired locations or with the desired uniformity.